Comparison of the Major Physical and Mechanical Properties of Juvenile Wood from Acacia mangium×A.auriculiformis and Acacia melanoxylon
The purpose of this study was to compare the differences in the main physical and mechanical properties of the juvenile wood of Acacia hybrid(Acacia mangium×A.auriculiformis)and A.melanoxylon in plantation forests and provide a theoretical basis for their cultivation and timber utilization.The main physical and mechanical properties of the wood of a 6-year-old Acacia hybrid and A.melanoxylon were determined according to Chinese national standards(GB/T 1927-2021).The results revealed that the air-dry densities of the heartwood of the Acacia hybrid and A.melanoxylon were 0.499 and 0.478 g·cm-3,respectively.The density of the Acacia hybrid was greater than that of A.melanoxylon,and the densities of the heartwood of the two were lower than that of the sapwood,which are both lightweight class Ⅱ timber.The volumetric drying shrinkage of the oven-dried heartwood was 8.5％and 8.4％,the air-dry volume dry shrinkage was 3.7％and 4.9％,respectively,and the differences in dry shrinkage between the tangential and radial directions were large.The volumetric air-dry swelling of the heartwood was 3.6％and 3.2％,and the volumetric water-saturated swelling was 8.2％and 8.9％,respectively.The pattern of the difference in the swelling rate between the two is not distinct.The maximum water absorption energy reached equilibrium at 30 days,and their average heartwood water absorption reached 150％and 172％,respectively,with Acacia hybrid wood ab-sorbing less water than A.melenoxylon.The values of compression strength parallel to the grain,bending strength,modulus of elasticity,hardness(tangential surface,radial surface,and cross section),and impact toughness of the Acacia hybrid wood in the smooth grain were 42.7,72.0,9 650,2 370.1,2 088.1,3 173.3 MPa,and 30.2 kJ·m-2,respectively.The average values of the above mechanical properties of the A.melanoxylon wood were 40.0,66.0,8 040.0,1 772.2,1 732.2,2 823.3 MPa,and 25.0 kJ·m-2,respectively.The main mechanical properties of both are Grade Ⅱ,the comprehensive quality coefficient is greater,and the com-prehensive quality coefficient of the Acacia hybrid is greater than that of the A.melanogaster and Acacia hybrid,indicating greater potential for further cultivation and utilization.
万方数据
维普
